A gerotor pump includes a rotor wherein only on the face wall of the rotor that lies adjacent to a pressure kidney and a suction kidney, a lubrication surface inclined in the direction of rotation of the rotor, relative to the surface plane of the face wall of the rotor, is disposed on each tooth, in each instance, over its tooth height, either starting directly in the center tooth plane or starting “offset” ahead of the center tooth plane in the direction of rotation of the rotor, which surface is formed from a level surface or multiple, always level partial surfaces that follow one another, which enclose an angle of inclination relative to the surface plane of the face wall of the rotor, in each instance, which angle lies in the range from 0.2° to 7°, in each instance.

An oil-free screw compressor has a screw rotor including a screw and a shaft, a bearing supporting the shaft, a first shaft seal device disposed between the screw and the bearing and including a first seal opposite to the shaft, and a first communication portion communicating the bearing side with respect to between the shaft and the first seal and the outer peripheral face of the first shaft seal device, and a second shaft seal device disposed between the first shaft seal device and the bearing and including a second seal opposite to the shaft, and a second communication portion communicating the screw side with respect to between the shaft and the second seal and the outer peripheral face of the second shaft seal device. A casing includes an atmosphere communication portion connected to both of the first communication portion and the second communication portion on the inner peripheral face of a shaft accommodation space, and communicating the first communication portion and the second communication portion with the atmosphere.

A gear pump or a gear motor includes a casing, a helical drive gear, a helical driven gear, a drive-side space, and an idler-side space. The drive and driven gears mesh with each other in the casing to partition inside of the casing so as to include high and low pressure spaces. The drive-side and idler-side spaces are each configured to allow pressure therein to become higher than a pressure in the low-pressure space. The drive-side space faces an end portion of a drive shaft rotatably supporting the drive gear. The idler-side space faces an end portion of an idler shaft rotatably supporting the driven gear. The end portion of the drive shaft is pushed in a predetermined direction by working fluid supplied to the drive-side space. The end portion of the idler shaft is pushed in the predetermined direction by working fluid supplied to the idler-side space.

A gear pump or a gear motor includes a casing, a helical drive gear, a helical driven gear, a drive-side space, and an idler-side space. The drive and driven gears mesh with each other in the casing to partition inside of the casing so as to include high and low pressure spaces. The drive-side and idler-side spaces are each configured to allow pressure therein to become higher than a pressure in the low-pressure space. The drive-side space faces an end portion of a drive shaft rotatably supporting the drive gear. The idler-side space faces an end portion of an idler shaft rotatably supporting the driven gear. The end portion of the drive shaft is pushed in a predetermined direction by working fluid supplied to the drive-side space. The end portion of the idler shaft is pushed in the predetermined direction by working fluid supplied to the idler-side space.

A pump includes a first housing part defining a first portion of a bore extending within the first housing part and shaped to receive a rotor; and a second housing part defining a second portion of the bore extending within the second housing part and shaped to receive the rotor. The first housing part has a first face abutable against an opposing second face of the second housing part to position the first portion of the bore with the second portion of the bore to receive the rotor. The first portion of the bore has a first circular cross-section portion centered along the first face and the second portion of the bore having a second circular cross-section portion centered, within the second housing part, at a distance from the second face.

A rotary engine that includes at least two sets of baffles that are arranged between a cylinder body and a rotor, and are in seal fit with the inner wall of the cylinder body to form at least two sealed cavities in the cylinder body; at least one set of the baffle is a movable baffle, and can rotate around the center of the cylinder body; a one-way rotation mechanism is arranged between the movable baffle and the rotor, and drives the rotor to rotate in one direction. The rotary engine has the benefits that the sealed cavities are formed by the movable baffle and the cylinder body; four working strokes including air suction, compression, ignition and exhaust are carried out in each sealed cavity; the movable baffle rotates under acting and counter-acting forces, drives the one-way rotation mechanism to rotate, and then drives the rotor to rotate.

A rotary engine that includes at least two sets of baffles that are arranged between a cylinder body and a rotor, and are in seal fit with the inner wall of the cylinder body to form at least two sealed cavities in the cylinder body; at least one set of the baffle is a movable baffle, and can rotate around the center of the cylinder body; a one-way rotation mechanism is arranged between the movable baffle and the rotor, and drives the rotor to rotate in one direction. The rotary engine has the benefits that the sealed cavities are formed by the movable baffle and the cylinder body; four working strokes including air suction, compression, ignition and exhaust are carried out in each sealed cavity; the movable baffle rotates under acting and counter-acting forces, drives the one-way rotation mechanism to rotate, and then drives the rotor to rotate.

A gear pump for transporting a fluid includes a pump casing; and a gear assembly which is accommodated in the pump casing. The gear assembly includes a driving gear, a driven gear that mashes with the driving gear, a driving gear shaft to which the driving gear is attached, a driven gear shaft to which the driven gear is attached, and a bearing frame that rotatably supports the driving gear shaft and rotatably supports the driven gear shaft.

A gear pump for transporting a fluid includes a pump casing; and a gear assembly which is accommodated in the pump casing. The gear assembly includes a driving gear, a driven gear that mashes with the driving gear, a driving gear shaft to which the driving gear is attached, a driven gear shaft to which the driven gear is attached, and a bearing frame that rotatably supports the driving gear shaft and rotatably supports the driven gear shaft.

In the two-cylinder hermetic compressor, a main bearing is disposed on one surface of a first cylinder, an intermediate plate is disposed on another surface of the first cylinder, the intermediate plate is disposed on one surface of a second cylinder, and an auxiliary bearing is disposed on another surface of the second cylinder. A shaft is constituted by a main shaft portion which has a rotor attached thereto and is supported by the main bearing, a first eccentric portion having a first piston attached thereto, a second eccentric portion having a second piston attached thereto, and an auxiliary shaft portion supported by the auxiliary bearing. A thrust receiving portion is provided on a side of the second eccentric portion facing the auxiliary shaft portion, and the auxiliary bearing is provided with a thrust surface on which the end face of the thrust receiving portion slides while contacting therewith. The thrust surface is provided with a ring groove.